Commit yarn 4 in the tree and install with --immutable (closes #149)

Follows sneak's ruling at
#149 (comment). This
repository now carries yarn 4.18.1 under .yarn/releases, and whichever
yarn the distribution packages hands the work to it. yarn.lock is
converted once, and script/bootstrap installs with --immutable instead
of stopping on yarn's major version. Node on Alpine is nodejs-current.
Every Dockerfile stage that needs yarn also copies .yarnrc.yml and
.yarn/releases/. The policies and both checklists say so, with the
steps for converting and for a new repository.

Model: opus-5-5

.dockerignore

@@ -35,12 +35,6 @@
 # `services/api/.claude/` and must add its own anchored entry.
 .claude
 
-# yarn's install state and cache stay out, and its release file stays
-# in. Docker obeys the last matching line, so these two lines sit above
-# the secret patterns, which must win under .yarn/releases/.
-.yarn/*
-!.yarn/releases
-
 # Environment files. `*.env` covers bare `.env` and the `prod.env`
 # convention. Re-include a committed template with a negation if the
 # build needs one: `!docs/example.env`.
@@ -61,8 +55,11 @@
 **/[iI][dD]_[eE][dD]25519
 **/[iI][dD]_[eE][dD]25519_[sS][kK]
 
-# Dependencies: restored inside the image, never copied in.
+# Dependencies: restored inside the image, never copied in. yarn's install
+# state and cache stay out, and its release file stays in.
 **/node_modules
+.yarn/*
+!.yarn/releases
 
 # OS metadata.
 **/.DS_Store

.gitignore

@@ -22,9 +22,9 @@ node_modules/
 .yarn/*
 !.yarn/releases
 
-# Secrets. Unanchored, so each matches at every depth. Matching is
+# Secrets. Unanchored like every entry above, so each matches at every
-# case-sensitive on Linux, so names use character ranges rather than a
+# depth. Matching is case-sensitive on Linux, so names use character
-# lowercase form that misses `Server.Key`.
+# ranges rather than a lowercase form that misses `Server.Key`.
 
 # Environment files. `*.env` covers bare `.env` and the `prod.env`
 # convention. Only the templates `example.env` and `sample.env` are

Dockerfile

@@ -6,8 +6,8 @@
 # system packages. script/ passes a new value on every build. That value
 # reruns every RUN step below the ARG line, and the install step keeps
 # its layer. node and yarn come from the distribution, which is trusted,
-# so they need no version and no hash. That yarn only starts the release
+# so they need no version and no hash. That yarn hands the work to the
-# file in .yarn/releases/, so every stage copies that file and
+# release file in .yarn/releases/, so every stage copies that file and
 # .yarnrc.yml before it runs script/bootstrap.
 #
 # alpine 3.24.3, 2026-11-04

TODO.md

@@ -21,11 +21,6 @@ fmt-check, and commit.
 
 # Completed Steps
 
-- 2026-11-06: The pinning rule in `prompts/REPO_POLICIES.md` now opens with its
-  scope: what we download and install ourselves in scripts and Dockerfiles
-  (https://git.eeqj.de/sneak/prompts/issues/154). Distribution packages are
-  outside the rule, and updating and upgrading them is allowed. Both checklists
-  say the same.
 - 2026-11-04: Each repository now commits yarn 4 and installs with
   `yarn install --immutable` (https://git.eeqj.de/sneak/prompts/issues/149), on
   sneak's ruling at
@@ -41,13 +36,6 @@ fmt-check, and commit.
       and yarn.
     - Both checklists give the steps, and the ignore files keep yarn's install
       state out of git and the build context.
-- 2026-11-04: An agent whose work is confined to one package may run `go test`
-  directly on that package's suite, or on individual tests in it, while
-  iterating (https://git.eeqj.de/sneak/prompts/issues/51), on sneak's ruling at
-  https://git.eeqj.de/sneak/prompts/issues/51#issuecomment-167600. The full
-  `make check` is still required before every push, and the `Makefile` gains
-  nothing. The rule on Docker now names the lint and test gates, because a run
-  while iterating is not one.
 - 2026-11-04: node, yarn, npm, python, pip and venv now come from the
   distribution with no version and no hash
   (https://git.eeqj.de/sneak/prompts/issues/146), on sneak's ruling at

prompts/EXISTING_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: Existing Repo Checklist
-last_modified: 2026-11-06
+last_modified: 2026-11-04
 ---
 
 Use this checklist when beginning work in a repo that may not yet conform to our
@@ -165,16 +165,15 @@ with your task.
           in the same commit, set the lint phase digest to the one named in the
           `.golangci.yml` paragraph of `REPO_POLICIES.md`)
     - [ ] JS: `package.json`, `yarn.lock`, `.yarnrc.yml`, `.yarn/releases/`,
-          `.gitattributes`, `.prettierrc`, `.prettierignore` (fetch the last two
+          `.prettierrc`, `.prettierignore` (fetch the last two from
-          from `https://git.eeqj.de/sneak/prompts/raw/branch/main/.prettierrc`
+          `https://git.eeqj.de/sneak/prompts/raw/branch/main/.prettierrc` and
-          and
           `https://git.eeqj.de/sneak/prompts/raw/branch/main/.prettierignore`).
-    - [ ] Any repository with `yarn.lock`: that file is in yarn 4's format. If
+    - [ ] JS: `yarn.lock` is in yarn 4's format. If its second line says
-          its second line says `yarn lockfile v1`, convert it with the steps
+          `yarn lockfile v1`, convert it with the steps below. Do them in one
-          below. Do them in one commit with the re-vendored scripts, because
+          commit with the re-vendored scripts, because yarn 1 ignores
-          yarn 1 ignores `--immutable` and exits 0 on a tree with no
+          `--immutable` and exits 0 on a tree with no `.yarnrc.yml`. Run them
-          `.yarnrc.yml`. Run them with any distribution's node and yarn, and use
+          with any distribution's node and yarn, and use `yarnpkg` on Debian and
-          `yarnpkg` on Debian and Ubuntu.
+          Ubuntu.
         1. Read the version from `yarnPath` in
            `https://git.eeqj.de/sneak/prompts/raw/branch/main/.yarnrc.yml`.
         2. Run `yarn set version <version>`. It writes
@@ -188,14 +187,12 @@ with your task.
            `npmMinimalAgeGate` from `.yarnrc.yml`. The conversion wrote them.
            They allow install scripts, any git repository and packages of any
            age, which yarn otherwise refuses.
-        6. In `package.json`, name any package that must run its install script,
+        6. Name any package that must run its install script in `package.json`,
            as `"dependenciesMeta": { "<name>": { "built": true } }`, and run
            `yarn install` again.
-        7. Add `.yarn/*` and `!.yarn/releases` above the secret patterns in
+        7. Add `.yarn/*` and `!.yarn/releases` to `.gitignore` and
-           `.gitignore` and `.dockerignore`. Docker obeys the last matching
+           `.dockerignore`, `.yarn/` to `.prettierignore`, and
-           line, and the secret patterns must win. Add `.yarn/` to
+           `.yarn/releases/** binary` to `.gitattributes`.
-           `.prettierignore`, and `.yarn/releases/** binary` to
-           `.gitattributes`.
         8. Run `yarn install --immutable`. It must pass and change nothing.
     - [ ] Python: `pyproject.toml`
     - [ ] Docs/writing: `.prettierrc`, `.prettierignore` (same URLs as above)
@@ -234,9 +231,8 @@ with your task.
 - [ ] `script/bootstrap` installs node, yarn and the node packages only when
       `yarn.lock` is in the tree. node and yarn come from the distribution when
       they are missing. It installs the node packages with
-      `yarn install --immutable`. The distribution's yarn only starts the
+      `yarn install --immutable`. Whichever yarn the distribution packages hands
-      release file that `yarnPath` in `.yarnrc.yml` names, and that file does
+      the work to the release file that `yarnPath` in `.yarnrc.yml` names.
-      the work.
 - [ ] A `Dockerfile` stage that needs yarn may start from any distribution that
       packages node and yarn. It copies `package.json`, `yarn.lock`,
       `.yarnrc.yml` and `.yarn/releases/` before it runs `script/bootstrap`. A
@@ -267,21 +263,21 @@ with your task.
 
 - [ ] Pre-commit hook is installed (`make hooks`)
 - [ ] No secrets in the repo (`.env`, keys, credentials)
-- [ ] No mutable references (tags, `@latest`) to what the repo downloads and
+- [ ] No mutable references in Dockerfiles or scripts (tags, `@latest`) — all
-      installs itself in scripts and Dockerfiles — all pinned by cryptographic
+      pinned by cryptographic hash with version/date comment. The one exception
-      hash with version/date comment. Distribution packages are outside this
+      is a package from the distribution's own package index, which needs no
-      rule. They need no version and no hash, and updating and upgrading them is
+      version and no hash. Pulling that index is also allowed. In a
-      fine too. In a `Dockerfile`, the distribution is the pinned base image's.
+      `Dockerfile`, the distribution is the pinned base image's. On a host, it
-      On a host, it is the host's, and the host's package manager stands for it,
+      is the host's, and the host's package manager stands for it, nix and brew
-      nix and brew included. A package source that a `Dockerfile` adds itself is
+      included. A package source that a `Dockerfile` adds itself does not get
-      not the distribution's own, so its packages are pinned
+      this exception
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means
       the distribution's newest Node package, such as `nodejs-current` on Alpine
       3.24
 - [ ] yarn's release file is in git under `.yarn/releases/`, written once by
-      `yarn set version` with an exact version (repositories with `yarn.lock`)
+      `yarn set version` with an exact version
 - [ ] Using `yarn`, not `npm` (JS projects)
 
 # Directory Structure

prompts/NEW_REPO_CHECKLIST.md

@@ -1,6 +1,6 @@
 ---
 title: New Repo Checklist
-last_modified: 2026-11-06
+last_modified: 2026-11-04
 ---
 
 Use this checklist when creating a new repository from scratch. Follow the steps
@@ -179,11 +179,10 @@ Template files can be fetched from:
           `https://git.eeqj.de/sneak/prompts/raw/branch/main/.golangci.yml` and,
           in the same commit, set the lint phase digest to the one named in the
           `.golangci.yml` paragraph of `REPO_POLICIES.md`)
-    - [ ] JS, or any repository that runs prettier through yarn: make the first
+    - [ ] JS: make the first `yarn.lock` with the steps below.
-          `yarn.lock` with the steps below. `script/bootstrap` installs no yarn
+          `script/bootstrap` installs no yarn until `yarn.lock` exists, so run
-          until `yarn.lock` exists, so run them with any distribution's node and
+          them with any distribution's node and yarn, such as Alpine's
-          yarn, such as Alpine's (`apk add nodejs-current yarn`). Use `yarnpkg`
+          (`apk add nodejs-current yarn`). Use `yarnpkg` on Debian and Ubuntu.
-          on Debian and Ubuntu.
         1. Read the version from `yarnPath` in
            `https://git.eeqj.de/sneak/prompts/raw/branch/main/.yarnrc.yml`.
         2. Run `yarn set version <version>`. It writes
@@ -211,9 +210,9 @@ are thin shims calling them. Model scripts:
     - It installs node, yarn and the node packages only when `yarn.lock` is in
       the tree. node and yarn come from that package manager when they are
       missing.
-    - It installs the node packages with `yarn install --immutable`. The
+    - It installs the node packages with `yarn install --immutable`. Whichever
-      distribution's yarn only starts the release file that `yarnPath` in
+      yarn the distribution packages hands the work to the release file that
-      `.yarnrc.yml` names, and that file does the work.
+      `yarnPath` in `.yarnrc.yml` names.
     - A non-server repo's development environment stage runs it, with only
       system packages installed inline above it.
     - A gate phase or the build stage installs what its base image lacks, either
@@ -285,20 +284,19 @@ are thin shims calling them. Model scripts:
       final stage is missing its `COPY --from=` edge to the gate phases.
 - [ ] No secrets in repo, and none in the build context: enumerate a probe image
       rather than reading `.dockerignore`
-- [ ] No mutable references to what the repo downloads and installs itself in
+- [ ] No mutable image/package references. The one exception is a package from
-      scripts and Dockerfiles. Distribution packages are outside this rule. They
+      the distribution's own package index, which needs no version and no hash.
-      need no version and no hash, and updating and upgrading them is fine too.
+      Pulling that index is also allowed. In a `Dockerfile`, the distribution is
-      In a `Dockerfile`, the distribution is the pinned base image's. On a host,
+      the pinned base image's. On a host, it is the host's, and the host's
-      it is the host's, and the host's package manager stands for it, nix and
+      package manager stands for it, nix and brew included. A package source
-      brew included. A package source that a `Dockerfile` adds itself is not the
+      that a `Dockerfile` adds itself does not get this exception
-      distribution's own, so its packages are pinned
 - [ ] node, yarn, npm, python, pip and venv come from the distribution wherever
       possible, never from nvm, pyenv, corepack or `npm install -g yarn`. If the
       distribution's version is too old, use a newer distribution. node means
       the distribution's newest Node package, such as `nodejs-current` on Alpine
       3.24
 - [ ] yarn's release file is in git under `.yarn/releases/`, written once by
-      `yarn set version` with an exact version (repositories with `yarn.lock`)
+      `yarn set version` with an exact version
 - [ ] No unnecessary files in repo root
 - [ ] All dates written as YYYY-MM-DD
 

prompts/REPO_POLICIES.md

@@ -1,6 +1,6 @@
 ---
 title: Repository Policies
-last_modified: 2026-11-06
+last_modified: 2026-11-04
 ---
 
 This document covers repository structure, tooling, and workflow standards. Code
@@ -21,28 +21,13 @@ style conventions are in separate documents:
   with the authoritative source as policies evolve.
 
 - **External references must be pinned by cryptographic hash.** This is the
-  single most important rule in this document. It covers what we download and
+  single most important rule in this document. It covers everything fetched from
-  install ourselves in scripts and Dockerfiles:
+  a remote source, including:
     - Docker base images
     - Go modules
-    - Python packages from PyPI
+    - Python packages
     - npm packages
     - GitHub Actions
-    - release archives fetched with `curl` or `wget`
-
-    Packages from the distribution's own package manager are outside this rule.
-    They need no version and no hash, because the distribution is trusted. In a
-    `Dockerfile`, it is the pinned base image's distribution. On a host, it is
-    the host's. The host's package manager stands for its distribution, and that
-    includes nix and brew. Updating the package index and upgrading installed
-    packages are fine too. This command, for example, is allowed:
-
-    ```sh
-    apt update && apt upgrade -y && apt install -y build-essential
-    ```
-
-    A package source that a `Dockerfile` adds itself is not the distribution's
-    own, so its packages are pinned like any other download.
 
     A version tag such as `@v4`, `@latest` or `:3.21` is server-mutable, and
     therefore a remote code execution vulnerability. Reference an external
@@ -59,6 +44,17 @@ style conventions are in separate documents:
     Unverified install scripts are arbitrary remote code execution. Double-check
     every external reference in every file before committing.
 
+    There is one exception: a package from the distribution's own package index
+    needs no version and no hash. Pulling that index is also allowed. The
+    distribution is trusted. In a `Dockerfile`, it is the pinned base image's
+    distribution. On a host, it is the host's. The host's package manager stands
+    for its distribution, and that includes nix and brew. These commands are
+    examples:
+    - `apt-get update`
+    - `apt-get install`
+    - `apk update`
+    - `apk add`
+
     These come from the distribution wherever possible:
     - node, meaning the distribution's newest Node package, such as
       `nodejs-current` on Alpine 3.24
@@ -83,6 +79,9 @@ style conventions are in separate documents:
     - the npm registry
     - `go get`
 
+    A package source that a `Dockerfile` adds itself is not the distribution's
+    own, so the exception does not cover it.
+
 - Every repo with software must have a root `Makefile` with these targets:
     - `make bootstrap`
     - `make setup`
@@ -133,8 +132,8 @@ style conventions are in separate documents:
     is out of step with `yarn.lock`.
 
     Each repository commits the yarn that runs. `yarnPath` in `.yarnrc.yml`
-    points at the release file in `.yarn/releases/`. The distribution's yarn
+    points at the release file in `.yarn/releases/`. Whichever yarn the
-    only starts that file, and that file does the work. Alpine packages yarn 1,
+    distribution packages hands the work to that file. Alpine packages yarn 1,
     and Debian 13 packages yarn 4.1. The same committed yarn does the work on
     both. Corepack never runs, and no yarn is downloaded.
 
@@ -144,8 +143,8 @@ style conventions are in separate documents:
     - `enableTelemetry: false`, because yarn otherwise sends usage reports from
       any host that is not CI
 
-    By default, yarn runs no dependency's install script. A dependency that must
+    Under these settings yarn runs no package's install script. A package that
-    run one is named in `package.json`, as
+    must run one is named in `package.json`, as
     `"dependenciesMeta": { "<name>": { "built": true } }`.
 
     `.gitattributes` carries `.yarn/releases/** binary`, so diffs and merges
@@ -200,16 +199,9 @@ style conventions are in separate documents:
     README must document the provided scripts in an **Entrypoints** section (see
     the README requirements below).
 
-- Run the repo's own entrypoints, never the underlying tools directly. The
+- Always use Makefile targets (`make fmt`, `make test`, `make lint`, etc.)
-  `script/` scripts are the single source of truth for how each operation runs.
+  instead of invoking the underlying tools directly. The Makefile is the single
-  Calling them directly is fine, and so is calling the Makefile targets. The
+  source of truth for how these operations are run.
-  Makefile targets must still exist, as the thin shims described above.
-
-    An agent whose work is confined to one package may run `go test` directly on
-    that package's suite, or on individual tests in it, while iterating. This is
-    the only exception to this rule. `go build`, `go vet` and the linter still
-    go through the entrypoints. A run while iterating is not a gate, so the full
-    `make check` is still required before every push.
 
 - The Makefile is authoritative documentation for how the repo is used. Beyond
   the required targets above, it should have targets for every common operation:
@@ -243,9 +235,9 @@ style conventions are in separate documents:
     - `package.json`, `yarn.lock`, `.yarnrc.yml` and `.yarn/releases/`
     - `go.mod` and `go.sum`
 
-- **The lint and test gates run in Docker, as phases of the `Dockerfile`.**
+- **Linting and testing run in Docker, as phases of the `Dockerfile`.** There is
-  There is no separate lint file. `script/lint` and `script/test` each build one
+  no separate lint file. `script/lint` and `script/test` each build one phase
-  phase and nothing else:
+  and nothing else:
 
     ```sh
     docker build --build-arg CACHEBUST="$(date +%s)-$$" \
@@ -1137,7 +1129,7 @@ style conventions are in separate documents:
     - `.gitea/workflows/check.yml`
     - Go: `go.mod`, `go.sum`, `.golangci.yml`
     - JS: `package.json`, `yarn.lock`, `.yarnrc.yml`, `.yarn/releases/`,
-      `.gitattributes`, `.prettierrc`, `.prettierignore`
+      `.prettierrc`, `.prettierignore`
     - Python: `pyproject.toml`
 
 - Guidance for coding agents lives in one `AGENTS.md` at the repository root. It

script/bootstrap

@@ -4,10 +4,10 @@
 # installed tools are skipped. Base tools, node and yarn come from nix,
 # apt, brew, or apk (detected in that order), with no version and no
 # hash, because the distribution is trusted. It installs node, yarn and
-# the node packages only when yarn.lock is in the tree. The
+# the node packages only when yarn.lock is in the tree. Whichever yarn
-# distribution's yarn only starts the release file that yarnPath in
+# the distribution packages hands the work to the release file that
-# .yarnrc.yml names, and that file does the work. So git pins the yarn
+# yarnPath in .yarnrc.yml names, so git pins the yarn that runs. Assumes
-# that runs. Assumes nothing is present.
+# nothing is present.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
@@ -80,7 +80,7 @@ main() {
 
     # A Dockerfile stage that needs no yarn copies no yarn.lock.
     if [ -f yarn.lock ]; then
-        if missing node; then pkg_install nodejs_latest nodejs node nodejs-current; fi
+        if missing node; then pkg_install nodejs nodejs node nodejs-current; fi
         if missing yarn && missing yarnpkg; then
             pkg_install yarn yarnpkg yarn yarn
         fi